Relation between pulsus paradoxus and pulmonary function in patients with chronic airways obstruction.

The relation of pulsus paradoxus to chronic, stable obstructive disease of the airways has not previously been described. Pulsus paradoxus was observed in 66% of 68 patients with such disease but in none of 14 healthy individuals. There was a significant correlation between the degree of pulsus paradoxus and the forced expiratory volume in 1 second (FEV1) in the subgroup of patients with bronchial asthma but not in the subgroup with chronic bronchitis or emphysema, or both. There was no correlation between the degree of pulsus paradoxus and the degree of hyperinflation in either group. Hence factors other than hyperinflation contribute importantly to the decrease in systolic pressure that occurs at full inflation of the lungs.     

Reassessment of inflammation of airways in chronic bronchitis.

The term chronic bronchitis has been criticised because it is associated with hypersecretion of mucus rather than bronchial inflammation. This study was designed to establish the presence or absence of clinical chronic bronchitis and measure pulmonary function in 45 patients about to undergo resection of the lung. The condition in the cartilaginous and small airways and the severity of the emphysema were then measured in the resected specimen. The results from 20 patients who had clinical chronic bronchitis were compared with those in 25 patients who did not. The data show that patients with chronic bronchitis had greater inflammation (a) on mucosal surfaces (p less than 0.05) of all bronchi larger than 2 mm luminal diameter and (b) around glands (p less than 0.005) and gland ducts (p less than 0.05) in bronchi larger than 4 mm diameter. A variable degree of inflammation was present in the submucosa of smaller bronchi. The groups had equivalent proportions of mucous glands and Reid''s indices in central airways, and no differences were noted in measurements of pulmonary function, condition of small airways, or emphysema. These data show that the term chronic bronchitis is justified by inflammation of cartilaginous airways and suggest that this abnormality may be the cause of the chronic productive cough.     

Ventilatory and gas exchange kinetics during exercise in chronic airways obstruction

The influence of chronic obstructive pulmonary disease (COPD) on exercise ventilatory and gas exchange kinetics was assessed in nine patients with stable airway obstruction (forced expired volume at 1 s = 1.1 +/- 0.33 liters) and compared with that in six normal men. Minute ventilation (VE), CO2 output (VCO2), and O2 uptake (VO2) were determined breath-by-breath at rest and after the onset of constant-load subanaerobic threshold exercise. The initial increase in VE, VCO2, and VO2 from rest (phase I), the subsequent slow exponential rise (phase II), and the steady-state (phase III) responses were analyzed. The COPD group had a significantly smaller phase I increase in VE (3.4 +/- 0.89 vs. 6.8 +/- 1.05 liters/min), VCO2 (0.10 +/- 0.03 vs. 0.22 +/- 0.03 liters/min), VO2 (0.10 +/- 0.03 vs. 0.24 +/- 0.04 liters/min), heart rate (HR) (6 +/- 0.9 vs. 16 +/- 1.4 beats/min), and O2 pulse (0.93 +/- 0.21 vs. 2.2 +/- 0.45 ml/beat) than the controls. Phase I increase in VE was significantly correlated with phase I increase in VO2 (r = 0.88) and HR (r = 0.78) in the COPD group. Most patients also had markedly slower phase II kinetics, i.e., longer time constants (tau) for VE (87 +/- 7 vs. 65 +/- 2 s), VCO2 (79 +/- 6 vs. 63 +/- 3 s), and VO2 (56 +/- 5 vs. 39 +/- 2 s) and longer half times for HR (68 +/- 9 vs. 32 +/- 2 s) and O2 pulse (42 +/- 3 vs. 31 +/- 2 s) compared with controls. However, tau VO2/tau VE and tau VCO2/tau VE were similar in both groups. The significant correlations of the phase I VE increase with HR and VO2 are consistent with the concept that the immediate exercise hyperpnea has a cardiodynamic basis. The slow ventilatory kinetics during phase II in the COPD group appeared to be more closely related to a slowed cardiovascular response rather than to any index of respiratory function. O2 breathing did not affect the phase I increase in VE but did slow phase II kinetics in most subjects. This confirms that the role attributed to the carotid bodies in ventilatory control during exercise in normal subjects also operates in patients with COPD.     

Pneumoconiosis and chronic bronchitis.

Data from a major long-term epidemiological survey in the British coalmining industry were examined to determine whether bronchitis offered any protective action against the development of pneumoconiosis. No evidence of such an effect was found.     

Changes in lung permeability after chronic pulmonary artery obstruction.

We have shown that left pulmonary artery ligation (LPAL) in mice causes a prompt angiogenic response, with new systemic vessels from intercostal arteries penetrating the pleura within 6 days. Because angiogenic vessels in other organs have been shown to exhibit increased permeability, we studied vascular permeability (Evans blue dye extravasation, lung wet weight-to-dry weight ratio, and lavaged protein) in naive C57BL/6 mice and 4 h, and 14 and 21 days after LPAL (4-6 mice/time point). We also measured radiolabel clearance as an index of functional perfusion after LPAL. Tracer clearance from the left lung was maximal by 6 days after LPAL and not different from right lungs. Thus a functional vasculature is established before 6 days of LPAL that results in normal tracer clearance. By 21 days after LPAL, Evans blue-albumin was significantly increased in the left lung relative to both 4 h (no vasculature) and 14 days after LPAL. Only after 21 days of LPAL was left lung wet weight-to-dry weight ratio significantly different from naive lungs. Additionally, lavaged protein was significantly increased both 4 h and 21 days after LPAL relative to control mice. Thus, using three different methods, results consistently demonstrated increased permeability to protein and water 21 days after LPAL. Although changes in surface area of perfusion might affect the interpretation of these results, blood flow measured with labeled microspheres indicated no change in left lung perfusion between 14 and 21 days of LPAL. Thus the lung vasculature, remodeled as a consequence of chronic pulmonary artery obstruction, demonstrates increased water and protein permeability.